9t-4.9t^2=1.8

Solution for 9t-4.9t^2=1.8 equation:

9t-4.9t^2=1.8

We move all terms to the left:

9t-4.9t^2-(1.8)=0

We add all the numbers together, and all the variables

-4.9t^2+9t-1.8=0

a = -4.9; b = 9; c = -1.8;
Δ = b2-4ac
Δ = 92-4·(-4.9)·(-1.8)
Δ = 45.72
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-\sqrt{45.72}}{2*-4.9}=\frac{-9-\sqrt{45.72}}{-9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+\sqrt{45.72}}{2*-4.9}=\frac{-9+\sqrt{45.72}}{-9.8}
$